Plastic material and method of waterproofing the same



Aug. l5, 1944. A, T, sMi'rH 2,355,756

PLASTIC MATERIAL AND METHOD OF WATERPROOFING THE SAME l original Filed Aug'. 26, 1942 INVENro f menne Aeg. 15, 1944 UNIT-ED PLASTIC MATERIAL AND METHOD F WATEBPBOOFING THE SAME Alva T. Smith, Milwaukee, Wis., assignor to The Sunlite Mfg. Company, Milwaukee, Wis., a corporation oi' Wisconsin Continuation of application Serial No. 456,288, 1942. This application March 25,

. August 26,

' 1943, Serial No. 480,479

s claims. (ci. 13s-6s) The present invention relates to plastic materials and more in particular to novel means for and methods of rendering such plastic materials waterproof and embodying or incorporating in their structure the characteristics of having heat reflecting properties.

Among the objects of the present invention is to provide a new article formed from plastic material and embodying a coating applied to at least one surface of said plastic material to render the same waterproof and to give to said plastic material the property of reflecting heat.

Another object of the present invention is to .provide a novel process of forming the article of manufacture immediately above identified.

At the present time there are a number'of thermoplastic and thermo-setting materials which find use as substitutes for essential war materals and in their own right have properties which make them particularly adapted for many and varied uses other than as substitute materials, such materials, however, in a good many uses involving their association with water and other fluids becoming milky and white because of their fluid absorption properties, thus making the particular materials rather Vunsightly and unfortunately giving the user the impression that the material. has deteriorated to such an extent as to require replacement 'and thereby givingA the seller considerable cause for concern from such complaints. In other instances waterproofness is a desirable characteristic for such plastic materials. irrespective of the ability of the waterproof material to prevent the milky or cloudy appearance therein as mentioned above. In addition, it has been found that such materials become brittle and easily fractured after the same have been used for a period of time in contact with water, moisture and other fluids. Such brittleness results, apparently, from the extraction of plasticizers used in forming the said materials which are gradually taken therefrom by the water or other fluids passing over or through the same. It has been found, however, that where such materials are waterproofed by the application of a suitable coating, the extraction of such plasticizers is greatly retarded, with the result that the material retains its flexibility over a. greater period of time.

The present invention has to do particularly with this problem of making such plastic materials Waterproof and to eliminate the milkyor white appearance therein which would otherwise occur upon fluid absorption and to prevent the material` from becoming brittle as above described. The said invention is further grounded upon the desire to incorporate and embody in such plastic materials additional structural features and characteristics leading to novel results by giving said plastic materials heat renovel process for coating the said conduit of plastic material for the purposes above described. For

thereby,l

tion, the same embodies the idea of applying 'vantages are comprehended by the invention, as

flecting properties to greatly increase their normal serviceable life and to improve the thermal eiciency thereof.

More particuarly, the invention is directed to the application of material to at least one of the surfaces of a conduit or other like device normally used forconducting fluids, to give to the said conduit waterproof and, heat reflecting properties. In more particular aspects of the invenplastic material to the surface of the conduit which has metallic material incorporated therein, and which plastic material impregnated with the metallic substance adheres to the surface of the conduit to give the same the properties hereinabove enumerated.

Further, the invention has as an object a example, the plastic material impregnated with some suitable waterproofing material may be sprayed or otherwise applied to theinterior surface of the pipe as-the same is continuously ex truded from a device having the proper dies to form a conduit of the size and shape desired.

Other objects, features, capabilities and adwill later appear and as are inherently possessed The present application is a continuation of application'Serial No. 456,288, filed August 26, 1942, for Thermo-plastic materials and method of waterproofing the same.

Referring to the drawing:

Figure 1 is a view in perspective with parts broken away of a conduit embodying the invention herein disclosed; and

Figure 2 is a diagrammatic sketch in elevation of a machine, with parts broken away, to show more in detail the means for coating the interior of the conduit shown in Figure l of the drawing.

Referring now more in detail to the drawing, an article made in accordance with the present invention is shown in Figure l as comprising a conduit 2 of plastic material, having a surface such as the inside surface -4 thereof, coated with material which is characterized as being waterproof. While the invention is disclosed in connection with a conduit of annularformation and having the coating applied to the inside surface thereof, nevertheless the invention comprehends the application of a coating of the character described to other surfaces of conduits, as well as other bodies of plastic material, for the purpose of rendering the same waterproof.

The present invention is more particularly directed to the application of a waterproof coating such as 4 to plastic material which normally tends to become milky or white due to the absorption of moisture, and which becomes brittle after use in contact with water or other fluids. 'I'he cellulose ethers, such as ethyl cellulose, which is f a thermo-plastic material. The thermo-plastic material sold under the name of Vinylite, which consists of a co-polymer of a vinyl halide and vinyl acetate, is also deficient in the above respects. Polyvinyl butyral is a further illustration of a thermo-plastic and thermo-setting material which is affected by water and other fluids in the manner indicated.

As immediately above indicated, while the invention is directed to the prevention of a milky appearance in the plastic material due to the absorption of moisture and to prevent the material from becoming brittle, nevertheless certain of the coatings to be hereinafter described have the further property of reflecting heat, which gives added advantages to the finished product.

The coating 4, as shown in Figure 1, may comprise a layer of material comprising a carrying agent and a metallic or non-metallic pigment. Any suitable pigment, such as aluminum powder, lead oxide or titanium oxide, representing the metallic materials can be used and all of which have the further property of reflecting heat and light. Aluminum is an excellent example of a material which has heat reflecting properties to a high degree. Representative of non-,metallic pigments which are suitable are carbon black, graphite, silica and powdered mica, al1 of which in varying degrees have the property of reecting light and heat, although carbon black and graphite are relatively deficient in this respect. The said coating is applied as a fluid impregnated with the pigment in ythe form of a powder or the like. While it has been found-that various types of carrying agents -for the pigment may be used, nevertheless the 'use `of a thin solution of the plastic material conforming to that from which the conduit is made and in which the pigment is suspended, gives a high degree of eiiciency and serves to completely secured the pigment or particles to the inside surface of the conduit without affecting the normal characteristics of the conduit.

It is, of course, understood that rendering of the plastic material waterproof is effected by the leang of the pigment or the building up of a barrier on the surface thereof. Waterproofing of the plastic materials is further assured in those cases where the coating is applied thereto while hot, inasmuch as such materials in such state are nin an expanded condition and when cooled contract to increase the anchoring of the coating thereto.

The layer or coating of such materials not only renders the conduit waterproof to prevent absorption of moisture which would otherwise cause the milky appearance and brittleness to which reference has been made above, but certain oi the said materials cause the reflection of heat rays, thus making the conduit as shown particularlyA desirable as a garden hose or for other till general outdoor uses, inasmuch as the coating causes `the reflection of a greater portion of the heat rays from the sun, thus preventing rot and greatly increasing the life of said conduit. Such latter coatings also have the further inherent characteristics of preventing loss of heat by radiation from the fluid being transmitted throu h the conduit where the same is used for conve ing hot fluids or the like.

The present invention further contempla a device for producing a conduit such as shown in Figure 1, the said apparatus for performing this operation being somewhat diagrammatically shown in Figure 2 of the drawing. 'Iherein is disclosed a receptacle 3 for holding a predetermined quantity of material and which container has associated therewith any suitable device for extruding the said plastic material under pressure through the die 6. The die 6 is formed with the annular orifice 8 which causes a continuous stream of plastic material to be extruded therethrough, as at I0. In this particular instance the conduit as shown is provided with a. coating applied to its interior surface so that the structure shown in Figure 2 embodies a nozzle l2 disposed just beyond the die 6 and which nozzle I2, through the medium of a conduit I4,

supplies the coating material under pressure to form a continuous coating to the inside surface n 4 of the conduit.

. Since the present invention contemplates a process for continuously forming the conduit 2. the said conduit I4 is provided within the inner die member I 6 and extends through the container 3 to a suitable source of material for the coating. The showing in Figure 2 is intended merely to disclose diagrammatically one form of apparatus by which the process can be practised. and of course the invention is not limited thereto but comprehends other devices which might be used for applying surface coatings to bodies of plastic material, such as the conduit as herein disclosed, as well as to other bodies of plastic material for producing the results contemplated by the present invention.

While I have herein described illustrative embodiments of the invention and processes for making the same, it is to be understood that thc invention is not limited thereto but may comprehend other details, features and process steps without departing from the spirit of the invention.

I- claim:

1. As an article of manufacture, a. body-of normally fiexible plastic material to at least one surface of which is applied a coating embodying a finely divided pigment-like material and a carrying agent of plastic material, said coating being characterized as being waterproof.

2. As an article of manufacture, a body of normally fiexible plastic material to at least"one surface of which is applied a coating embodying metallic material in a finely divided state and a carrying agent of plastic material, said coating being characterized as being Waterproof and having heat reflecting properties.

3. As an article of manufacture, a conduit formed of normally flexible plastic material having an interior coating embodying nely divided particles of material and a carrying agent of plastic material, said coating being characterized as being waterproof.

ALVA T. SMITH. 

